Apparatus for handling sacks

ABSTRACT

Apparatus for cleaning the inner surfaces of mouth portions of sacks prior to closure, e.g., by heat sealing, has suction means to engage the two lips of the mouth portion to part them, and a finger having suction cleaning means on opposite sides which is inserted between the parted lips. The finger and sack are then relatively traversed so that the finger scans a band along each of the said inner surfaces. The means to part the lips may be vacuum heads and there may be a bellows-construction in the vacuum linkage which contracts when the head is applied to the mouth portion, thereby withdrawing the head and causing the lips to part.

United States Patent [191 Webber et al. [451 July 16, 1974 [54]APPARATUS FOR HANDLING SACKS v [75] inventors: Geoffrey Terence Webber;James pmflary Examirfer'fiarvey Hornsby Henry Winchester Thorne, both of4 Exammer"? Bristol, England Attorney, Agent, or Firm-Omn M. Behr [73]Assignee: Whitehall Machinery Limited Bristol, England [57] ABSTRACTApparatus for cleaning the inner surfaces of mouth [22] Flled' 1972portions of sacks prior to closure, e.g'., by heat sealing, [2]] Appl.No.: 223,248 has suction means to engage the two lips of the mouthportion to part them, and a finger having suction cleaning means onopposite sides which is inserted bel5/304,A1:4i3g?3la tween the partedPa The finger and sack are then Fi d 6 B 303 relatively traversed sothat the finger scans a band e o a 53/167 along each of the said innersurfaces. The means to part the lips may be vacuum heads and there maybe a [56] R t Ct d bellows-construction in the vacuum linkage which 1 eerenceis I e contracts when the head is applied to the mouth por- UNITEDSTATES PATENTS tion, thereby withdrawing the head and causing the3,432,982 3/1969 Brinkmeier et a1. 53/167 X lips to part. 3,488,9101/1970 Stoger et a] 53/167 X 3,505,136 4/1970 Attwood 53/167 x 3 Claims,5 Drawlng Figures PATENIE JUL 1 61974 SHEET l- UF 4 I I 1 APPARATUS FORHANDLING SACKS This invention relates to apparatus and method forpreparing sacks for heat-sealing, particularly sacks of which at leastmouth portions are made up of, or lined with, heat-sealable material andwhich are intended to n be closed by heat-sealing.

One problem which arises in the closure of sacks in automatic manner isthat of ensuring that the surfaces which are closed together areadequately clean. This is particularly serious when heat-sealing is tobe used as the means of closure since dust or granules between theintroducing the finger between the lips so opened and means for causingrelative movement of the finger and the sack so that the finger scans aband along each of the mutually inner surfaces of the mouth portion ofthe sack, the finger having on opposite sides suctioncleaning means forremoving particles from these bands.

The means for parting the lips may be one or more vacuum suction heads,preferably one to each side of the sack, and may include abellows-construction linkage for at'least one of the said heads suchthat when the vacuum isapplied between the head and the material of thesack the bellows contracts thereby withdrawing the head with thematerial attracted to it. The finger may be inserted into the sack mouthby rotational movement and may then remain stationary while the sack iscaused to execute longitudinal movement past it, the finger being causedto execute further rotational movement for, retraction from the mouth byabutment with an end wallof the mouth of the sack. Movement 'of thefinger may cause opening and closure of valves concerned with the supplyof vacuum to vacuum heads used in drawing apart the lips of the sack.The finger may attract the-material of the sack at the mouth portion toitself by being provided with a vacuum port or ports, and acting at thesame time to draw the particles off the material. The finger may beprovided additionally with a mechanical scraper to act on the surface ofthe band of themouth portion, the portion being held in abutment withit. The finger may be a composite finger, that is to say, may comprisetwo or more elements to act respectively on the said surfaces ondifferent sides of the sack mouth.

A particular embodiment of the invention will now be described withreference to the accompanying drawings, wherein:

FIG. 1 shows in diagrammatic plan view, apparatus for cleaning the mouthof sacks;

FIG. 2 shows in end view, looking in the direction of travel of a sack,part of the apparatus of FIG. 1 the lips of a sack mouth being closed;'

FIG. 3 is the same view as shown in FIG. 2 but the lips of the sackmouth are drawn apart and the chains 17 are engaging the sack,

- FIG. 4 is a sectional view taken at right angles to FIG.

2 of partof the apparatus of FIG. 1 along the line 4-4 2 in FIG. 1,showing a cleaning finger immediately after descending into the mouth ofthe sack,and

FIG. 5 is the same view as FIG. 4, but shows the finger at the end ofits action on the sack.

In FIGS. 2 and 3 a sack 1 is travelling into or out of the plane of thepaper. The path of a sack is shown by arrow A in FIG. 1. The sack'l hasbeen filled and is in transit to a heat sealing machine 20 (FIGS. 1, 4and 5). It is supported below by a conveyor (not shown) which transportsit through the mouth cleaning apparatus and on to the heat sealingmachine. The sack is made entirely of plastics material of aheat-scalable nature. Its mouth portion is shown at 1a. The lips 8 ofthe mouth portion can be drawn apart but at each end of the sack(loading and trailing in the direction of travel) there are end walls11, 12 which link the two lips. In the case of the gusseted sack, theend walls will be infolded in The neck 16 of a sack 1 below the mouthportion 1a is gripped between two carrier chains 17, one on each side,as it approaches the guideway 4b. The chains maintain the position ofthe neck during the mouth cleaning operation.

In operation vacuum is applied as described below to the vacuum heads 2as the sack approaches and when the sack is between them the two cups 3each draw the material of one lip of the sack towards themselves. Whenthe leading edge of the sack has passed beyond the cups 3, this causes apartial or complete obstruction of gas entry to each cup from theatmosphere so that reduced pressure is applied inside each bellows 7which therefore contracts and moves the cups 3 axially towards the fixedduct 6. This condition is shown in FIG. 3 which shows also that thisaxial movement causes tilting of the cup and of the: plate shown atpositions 3', 4, so that the lips 8 are drawnapart. This enables acleaning finger 9 to be inserted between them.

FIG. 4 shows a side view taken in a direction at rightangles to FIGS. 2and 3 at a time: when the lips 8 are being held apart (some parts areomitted for clarity).

A finger 9 is mounted on a sleeve 10 which rotates about a tube 10aforming a pivot positioned above the level of the heads 2, and lyingperpendicular to the direction of travel of a sack. The finger 9 isdriven by a double acting air-operated cylinder 18, the piston rod 39 ofwhich is pivoted to a rod 10b mounted on the tube so that operation ofthe cylinder rotates the finger 9 about the tube 10a as described below.Rotational movement of the finger 9 into the sack in the sense of thearrow B from its initial position shown in FIG. 4 in dotted lines to theposition shown in full lines, wherein it is vertical, is effected by thecylinder 18 when the sack mouth 1a has been opened as described above.This rotational driven movement is a swift movement so that the fingerovertakes the sack as this is moved by conveyor means, not shown, in thesense of the arrow A. When the finger adopts the full I ues until thefinger is lifted'clear of the sack i.e.,

reaches the position shown in broken lines in FIG. 5, after which it isreturned by the return action of the spring 9a to the dotted. lineposition shown in FIG. 4.

The initial rotation of the finger causes overtaking of the sack inorder that the finger will be brought right into the fold of the leadingwall 11 of the mouth portion.

The tube 10a is adapted to act as a valve to control the admission andrelease of vacuum to the vacuum heads 2. Ports in the tube 100 registerwith ports in the sleeve 10 to supply vacuum to the finger 9 when thefinger is in the vertical position of FIG. 3, and further ports are inregister to supply vacuum through the lines 6 to the heads 2-when thefinger 9 is in the dotted line position of FIG. 4, these latter portsbeing brought out of register cutting off vaccum to the heads 2 when thefinger has adopted its vertical position. The vacuum is supplied througha pipe 21 to the tube 10a and passes to the bellows 7 through pipes 6.When the finger 9 comes back to the dotted line position of FIG. 4, thevacuum line 21 is again connected to the heads 2 in readiness for thenext sack 1 (FIG. This arrangement ensures opening of the lips 8 by thevacuum heads 2 when a sack passes between the heads 2 and then releaseof the lips when the finger 9 is rotated to its vertical positionbetween them. As mentioned above also, vacuum is introduced throughports in the tube 10a and sleeve 10 to ducting contained in the finger 9and connected to ports 14 in its sides towards its outer end. Ports 14are provided on both sides of the finger, each set of ports beingdesigned to remove particles, e.g., particles of the material with whichthe sack is filled, by vacuum suction from a band on each of the twomutually inner surfaces of the mouth portion which is swept by thoseports and which is indicated at 15 in FIG. 5. The vacuum applied to theports 14 tends to draw the material of the sack towards the finger 9.

The operation of the cylinder 18 to rotate the finger 9 into thevertical position is controlled through a solenoid valve 19 by amicroswitch 22 which has a feeler arm 23 pivoted at 24 and engaging aswitch button 25. The end 26 of the feeler arm 23 is in the path of thesack. When the leading end of a sack passing through the apparatusengages the feeler arm 23, the button 25 is pressed and the microswitchemits a signal which causes the solenoid valve 19 to admit compressedair from the mains inlet 27 into the cylinder 18 so as to rotate thefinger to its vertical position (FIG. 4). This causes cutting off of thevacuum to the heads 2 as described above. When the sack has passed thefeeler 23,

the microswitch emits another signal which causes reversal of thecylinder 18 to its initial position.

A finger in apparatus embodying the invention may be composite, beingmade up of two or more elements disposed laterally of each other, meansfor cleaning being on the mutually outer surfaces. This form of fingeris particularly useful for a gusset folded sack, since the elements canenter into double fold forming the end of the mouth. portion of such asack.

In a embodiment of the invention alternative to that shown in thedrawings, a straight line (usually vertical) insertion motion might beused'(witliout rotation) to insert the finger into the sack, the fingerthen being i held stationary, or moved counter to the movement of thesack, and then beingretra'cted in a straight line, e.g., vertically. Themovements of the finger may again in this case mechanically control theapplication or release of vacuum. But in either case electrical contactmay be made, through solenoid-operated valves.

Further, cleaning means on the finger need not be only vacuum elementsbut could include brushing,

scraping or wiping elements, and in this case it would be desirable toprovide for counter-pressure on the outside of the sack to pressmaterial of its mouth portion onto such elements. This might be by meansof a roller or leaf spring. With some products with which the sack hasbeen filled, satisfactory cleaning can be obtained using a jet ofcompressed air from the finger as well as the vacuum suction. Thecleaning finger could have a separate channel for the supply ofcompressed air to remove loose dust first in addition to a channel forthe vacuum supply to remove remaining dust.

Means for pulling apart the lip portions 8 may move with the sack;otherwise plates 4 may take the form of slide plates past which the sackmoves since the drawing apart and consequent contact of the material ofthe sack on those plates need last only for a sufficient period to allowthe introduction of the finger.

As a result of the relative movement of the finger and the sack a band15 is cleaned of particulate material and the sack is then passed to aclosure machine which closes it along that band. In normal circumstancesthe present apparatus will have been installed because that closure willbe made by the heat-sealing either of a heat-sealable adhesive appliedto a non-heat-sealable sack material or of the material itself of thesack mouth portions.

It will be desirable to ensure regularity of the position of operationof the finger so that the clean band 15 is an ascertained position inthe sack and for this purpose levelling guides will preferably beprovided on the conveyor mechanism or the feeding of the sack to thatmechanism will be at a controlled level.

What we claim is:

1. Apparatus for preparing mouth portions of sacks for closure whichincludes suction means for opening lips of the mouth portion of a sack,a cleaning finger, means for introducing the finger between the lips soopened and means for causing relative movement of the finger and thesack so that the finger scans a band along each of the mutually innersurfaces of the mouth portion of the sack, the finger having an oppositesides suction-cleaning means for removing particles from these bands.

2. Apparatus according to claim 1 wherein said suction means for openingthe lips comprises at least one vacuum suction head.

3. Apparatus according to claim 2 wherein for the said at least onesuction head there is a bellowsconstruction linkage such that when thevacuum is applied between the head and the material of the sack thebellows contracts thereby withdrawing the head with the materialattracted to it.

4. Apparatus according to claim 2 wherein at least one such vacuumsuction head is provided on both lateral sides of the said mouth.

5. Apparatus according to claim 2 wherein movement of the finger from aninoperative to an operative 6 sack is caused to execute longitudinalmovement past it, and then being retracted from the mouth of the sack byrotational movement, this retracting movement being caused by abutmentof the said finger with an end wall of the mouth.

8. Apparatus according to claim 1 wherein movement of the finger from aninoperative to an operative position causes supply of vacuum to thesuctioncleaning means on the finger.

1. Apparatus for preparing mouth portions of sacks for closure whichincludes suction means for opening lips of the mouth portion of a sack,a cleaning finger, means for introducing the finger between the lips soopened and means for causing relative movement of the finger and thesack so that the finger scans a band along each of the mutually innersurfaces of the mouth portion of the sack, the finger having an oppositesides suctioncleaning means for removing particles from these bands. 2.Apparatus according to claim 1 wherein said suction means for openingthe lips comprises at least one vacuum suction head.
 3. Apparatusaccording to claim 2 wherein for the said at least one suction headthere is a bellows-construction linkage such that when the vacuum isapplied between the head and the material of the sack the bellowscontracts thereby withdrawing the head with the material attracted toit.
 4. Apparatus according to claim 2 wherein at least one such vacuumsuction head is provided on both lateral sides of the said mouth. 5.Apparatus according to claim 2 wherein movement of the finger from aninoperative to an operative position causes cut-off of the supply ofvacuum to the suction head.
 6. Apparatus according to claim 5 whereinsaid cut-off of the supply of vacuum to the suction head is effected bya valve action actuated by said movement of said finger.
 7. Apparatusaccording to claim 1 wherein said means for introducing the fingerbetween the lips operates to insert the finger into the sack byrotational movement, the finger remaining stationary while the sack iscaused to execute longitudinal movement past it, and then beingretracted from the mouth of the sack by rotational movement, thisretracting movement being caused by abutment of the said finger with anend wall of the mouth.
 8. Apparatus according to claim 1 whereinmovement of the finger from an inoperative to an operative positioncauses supply of vacuum to the suction-cleaning means on the finger.